Electrical circuits for arcs with pool-type electrodes



ELECTRICAL CIRCUITS FOR ARCS WITH POOL-TYPE ELECTRODES Filed Jan. 21,1950 kwwivfi WM mfifiw E w e e wz m n r a a a X 8 \N 7% (4 J w w M l n 5I a 2 m 3 kZMwESQ m R Q n m N 3 N w cated by the letters A. C3.

the surfaces.

Patented May 18, 1954 UNITED ELEC'IERICAL CIRCUITS FOR ARCS WITHPOOL-TYPE ELECTRODES Beatrice Pearson De Lany, Miami Beach, Fla.., andPaul L. Copeland, Chicago, 111.

Application January 21, 1950, Serial No. 139,941

21 Claims. 1

This invention relates to electrical circuits for pool-type electrodesand has for one object to provide a circuit associated with a pool-typeelectrode to assure quick starting and rapid initiation of an electricarc.

Another object is to provide a circuit suitable for use in connectionwith lighting devices which includes pool-type electrodes, and toprovide thereby means for suitable operation with alternating current atrelatively low voltages.

Other objects will appear from time to time in the specification andclaims.

The invention is illustrated more or less diagrammatically in theaccompanying drawing, wherein:

Figure 1 is a section through one type of a tube or source ofillumination; and

Figure 2 is a section through a modified form shown on a reduced scale;

i is a tube or envelope of any desirable material. It may convenientlybe made of glass or other transparent or translucent material. isprovided with two portions 2--2 which serve as pool retaining means forpools of material 3, such as mercury or other metal, which will remainfluid at normal operating temperature. i-d are conductors which projectinto the pool portions 2 and are in electrical contact with the pools 3.These members are connected by wires 5 and 6 to a source of alternatingcurrent indi- In the wire 5, or elsewhere in this portion of thecircuit, is positioned a current limiting ballast I.

In each of the portions 2, and in contact with their respective pools 3,are funnel-like members 8. These members are preferably formed ofsemi-conducting material or insulating members or funnels, and areprovided with surfaces of semi-conducting material or metal filmindicated at 9.

In each of the semi-conductive structures or conductive coatings 9 is awire or conductor H) which, as shown, may have extensive contact withEach of the members It passes outwardly through the tube or envelope l,and the members it are joined together by a wire or other conductor Hwhich, as shown, is outside of the envelope I. This wire may bepositioned within the tube or envelope and it may have negligibleresistance or it may have a substantial resistance of several hundredohms. Each of the members 10 is also connected conductively to one ofthe members 4 by a wire or other conductor l2. In each of the members [2is positioned acontact-type rectifier 13 If the wire H is positionedwithin the tube or envelope l the wires It will then not extendoutwardly beyond the tube l but will be connected to the wire ll withinthe tube and correspondingly the rectifiers 13 may also be positionedwithin the tube or envelope Whatever the arrangement in this respect,the circuit will be substantially as shown.

The members 8 are, as shown, of more or less tunnel shape, and theycomprise resistances or resistance members positioned within theenvelope or tube l and in contact with the mercury or other metal 3which forms the pool. Although these members are shown of funnel shape,other types of resistors may be substituted for them. Among the suitabletypes are those shown in our copending application Serial No. 139,942,which is filed of even date herewith. As thereshown, the resistorscomprise resistance discs formed of carborundum or other material andthey are solid, with a passage or perforation formed through them.Resistors of types other than these two may be used and the invention isnot limited to the particular shape shown in the present application orin our aforesaid copending application. Resistors of this general type,however, have proven to be more efiective than those of other shapes,such as rods.

In the device of this invention, in any of the forms or arrangementssuggested, the metal pool '3 will function as a source of electrons inan are operating on alternating current. The circuit and constructionshown provides the necessary mechanism for initiating the discharge ofelectrons at the potential differences applied to th device; Operationhas been found to be satisfactory even for currents as low as milliamperes provided the area of the pool 3 exposed to the interior of theenvelope 1 is restricted as; for example, by the members 8 or by thecorresponding members shown in our copending application abovementioned. We have operated arcs with pool-type electrodes of the typeshown from alternating currents supplied at potentials of a few hundredvolts in a circuit generally like that shown but without the rectifiersl3. With that modification, the potential is connected through theballast l to the electrodes formed by the pools 3 at each end of thetube, and experience has shown that this suffices to initiate the arcduring each half cycle of the alternating current and to maintain ituntil the potential falls below a critical value near the end of eachhalf cycle.

Experience has shown that the potential difference on which the devicewill operate satisfactorily may be lowered substantially, however, bythe use of a pair of rectifiers, such as the rectifiers l3 shown in thedrawing. Any pair of devices such that the resistance offered to currentpassing in opposite directions differs may be used as rectifiers for thepurpose indicated. One such device now known and sold on the market isVaristor.

As above pointed out, the circuit shown includes the rectifiers andtheir use reduces the part of the potential drop which occurs on theresistance material, such as the semi-conductive surface G of themembers 8, within the tube at the end of the tube which is temporarilypositive and thus throws a greater proportionate part of the potentialdrop across the resistance formed by the opposite surface 9 on themember 3 in the negative end which is, at the time, serving as acathode. It is to be understood that when the device of the presentinvention is operated with alternating current, each electrode structureis alternately an anode and a cathode. Thus, the increased drop in theresistance material 9 at the positive end of the tube results in theearly production of a cathode spot upon the pool of liquid metal 3.

In the modified form of Figure 2 the only change is that the wire whichconnects the coatings 9 is positioned wholly within the envelope and therectifiers are also positioned within the envelope. Thus, a wire orconductor ill positioned wholly within the envelope is connected to eachof the semi-conductive surfaces 8. As shown, this wire preferablyincludes portions l5 which are in extensive contact with the surfaces 9.At each end the wire M, at a point below the upper margin of the members8, is provided with a portion i6 which extends into contact with thepool 3. Rectifiers E? are positioned in each of the wires or conductingmembers E5, and these rectifiers are the same in construction andpurpose as the rectifiers l3 shown in Figure 1. From a comparison of thetwo figures, it is obvious that they include the same members and thatthe difference between the forms of the two figures is primarily thatthe wire, which connects the conductive surfaces 9, and the rectifiersare all located within the envelope.

The expression semi-conductor is used in this art today to describematerials which are relatively poor electrical conductors. Among thematerials above mentioned carbon and carborundum are today properlydescribed by the expression semi-conductors. Silicon and germanium areother presently known materials which would now be described by theexpression semi-conductor as that expression is presently understood.

Although we have shown an operative form of our invention, it will berecognized that many changes in the form, shape and arrangement of partscan be made without departing from the spirit of the invention, and ourshowing is, therefore, to be taken as, in a sense, diagrammatic.

The use and operation of this invention are as follows:

With the circuit generally as shown in Figures 1 and 2, and with thedevice connected to a source of alternating current, the operation isnormally substantially as follows;

That electrode which is negative momentarily will have a cathode spotestablished within it.

The electron current originating thereon passes through the residual gasand vapor contained within the envelope I and is collected by theopposite electrode at the end which is temporarily positive which, atthat time, serves as an anode."

When the potential reverses polarity the cycle is repeated with the twoelectrodes interchanged so that the one which has acted as an anode nowacts as a cathode and the one which has acted as a cathode new acts asan anode.

The use of the contact rectifiers causes a distribution of potential andcurrent which causes the initiation of the cathode spot on the poolearlier in the cycle than would otherwise be the case in the absence ofthe rectifier. The device would work without a rectifier if thepotential is high enough. Therefore, the presence of the rectifierpermits operation at substantially lower potential,

The discharge tube itself contains no means for limiting the current,and this must be included in the external circuit as the currentlimiting ballast.

We claim:

1. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at operatingtemperature, in each of said retaining parts, said envelope defining apassage from one pool to the other, conductors extending through saidenvelope, one in contact with each of said pools. means for electricallyconnecting said conductors to a source of alternating current, a currentlimiting ballast in said connecting means, restricting memberspositioned within said envelope, one above each of said pools, saidmembers in contact with said pools, there being a passage past eachmember, each restricting member having a conductive portion thereon, andmeans for electrically connecting the conductive portions of saidrestricting members to each other and for connecting said conductiveportions to said conductors.

2. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at room temperature,in each of said retaining parts, said envelope defining a passage fromone pool to the other, conductors extending through said envelope, onein contact with each of said pools, means for electrically connectingsaid conductors to a source of alternating current, a current limitingballast in said connecting means, restrictin members positioned withinsaid envelope, one above each of said pools, said members in contactwith said pools, there being a passage past each member, the area ofsaid passage at its point of contact with its respective pool being lessthan the total area of the pool, each restricting member havin aconductive portion thereon, and means for electrically connecting theconductive portions of said restricting members to each other and forconnectin said conductive portions to said conductors.

3. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at operatingtemperature, in each of said, retaining parts, said envelope defining apassage from one pool t the other, conductors extending through saidenvelope, one in contact with each of said pools, means for electricallyconnecting said conductors to a source of alternatin current, a currentlimiting ballast in said connecting means, restricting memberspositioned within said envelope, one

above each of said pools, said members in contact with said pools, therebeing a passage formed through each member, each restricting member 5.having a conductive portion, means for electrically connecting theconductive portions of said restricting members to each other and forconnecting said conductive portions to said conductors, and rectifierspositioned in the connection from each restricting member to on of saidconductors.

4. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at operatingtemperature, in each of said retaining parts, said envelope defining apassage from one pool to the other, conductors extendin through saidenvelope, one in contact with each of said pools, means for electricallyconnecting said conductors to a source of alternating current, a currentlimiting ballast in said connecting means, restricting memberspositioned within said envelope, one above each of said pools, saidmembers in contact with said pools, there being a passage formed througheach member, the area of said passage at its point of contact with itsrespective pool being less than the total area of the pool, eachrestricting member having a conductive portion, means for electricallyconnecting the conductive portions of said restricting members to eachother and for connecting said conductive portions to said conductors,and rectifiers positioned in the connection from each restricting memberto one of said conductors,

5. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at operatingtemperature, in each of said retaining parts, said envelope defining apassage from one pool to the other, conductors extending through saidenvelope, one in contact with each of said pools, means for electricallyconnecting said conductors to a source of alternatin current, a currentlimand'for joining the connections from said restrict ing members,

-7. In combination, an envelope of insulating material substantiallyfree from air and shaped 10 through said envelope, one in contact witheach iting ballast in said connecting means, restrict- I ing memberspositioned within said envelope, one above each of said pools, saidmembers in contact with said pools, there being a passage formed througheach member, the area of said passage.

at its point 01 contact with its respective pool being less than thetotal area of the pool,-each restricting member having a conductiveportion, means for electrically connecting the conductive portions ofsaid restricting members to each other and for connecting saidconductive portions to said conductors, and rectifiers positioned in theconnection from each restricting member to one of said conductors, saidconnecting means and said rectifiers being positioned outside of saidenvelope.

6. In combination, an envelope of insulating material substantially freefrom air and shaped to define a pair of pool retaining parts, a pool ofmetal, which remains liquid at normal operating temperature, in each ofsaid pool retaining parts, said envelope defining a passage from onepool to the other, electrical conductors extending through saidenvelope, one in contact with each of said pools, members above each.pool, each adapted to restrict the exposed area of its respective pool,each of said restricting members comprising a part in contact with itsrespective pool and a part continuous therewith, out of contact withsaid pool and overlying and masking a portion of the upper surface ofits pool, means for electrically connecting said conductors to a sourceof alternating current, and a plurality of means for joining saidconductors to each other of said pools, members above each pool, eachadapted to restrict the exposed area of its respective pool, each ofsaid restricting members comprising a part in contact with itsrespective pool and a part overlying and maskin a portion of the uppersurface of its pool, means for electrically connecting each restrictingmember to the other, means for electrically connecting said conductorsto a source of alternating current, a plurality of means forelectrically joining said eonductors to each other and for electricallyjoining the connections from said restrictin members, and a rectifierpositioned in each of said last mentioned connecting means.

8, In combination, an envelope of insulating material substantially freefrom air and shaped to define a pair of pool retaining parts, a pool ofmetal, which remains liquid at normal operating temperature, in each ofsaid pool retaining parts, said envelope defining a passage from onepool to the other, electrical conductors extending through saidenvelope, one in contact with each of said pools, members above eachpool, each adapted to restrict the exposed area of its respective pool,each of said restricting members comprising a part in contact with itsrespective pool and a part overlying and masking a portion of the uppersurface of its pool, means for electrically connecting each restrictingmember to the other, means for electrically connecting said conductorsto a source of alternating current, a plurality of means forelectrically joining said conductors and for joining the connectionsfrom said restricting members, and a rectifier positioned in each ofsaid last mentioned connecting means, said rectifiers being positionedoutside said envelope.

9. In combination, an envelope of insulating material substantially freefrom air and shaped to define a pair of pool retaining parts, a pool ofmetal, which remains liquid at normal operating temperature, in each ofsaid pool retaining parts, said envelope defining a passage from onepool to the other, electrical conductors extending through saidenvelope, one in contact with each of said pools, members above eachpool, each adapted to restrict the exposed area of its respective pool,each of said restricting members comprising a part in contact with itsrespective pool and a part overlying and masking a portion of the uppersurface of its pool, each restricting member being provided with asemiconductive surface, means for electrically connecting thesemi-conductive surface of each restricting member to that of the other,means for electrically connecting said conductors to a source ofalternating current, and a plurality of means for electrically joiningsaid conductors and for electrically joining the connections from saidrestricting members.

10. In combination, an envelope of insulating material substantiallyfree from air and shaped to define a pair of pool retaining parts, apool of metal, which remains liquid at normal operating temperature, ineach of said pool retaink lng parts, said envelope defining a passagefrom one pool to the other, electrical conductors extending through saidenvelope, one in contact with each of said pools, members above eachDcol, each adapted to restrict the exposed area of. its respective pool,each of said restricting.

members comprising a part in contact with its respective pool and a partoverlying and masking a portion of the upper surface of its pool, each.restricting member being provided with a semi-conductive surface, meansfor electrically connecting the semiconductive surface of eachrestricting member to that of the other, said means lying outside saidenvelope, means for electrically connecting said conductors to a sourceof alternating current, and a plurality- Qf. means for electricallyjoining said conductors and for joining the connections from saidrestricting members.

.11., In combination, an envelope of insulating material substantiallyfree from air and shaped to: define a pair of pool retaining parts, apool of metal, which remains liquid at normal operating temperature, ineach of said pool retaining; parts, said envelope, defining a. passagefrom, one pool to the other, electricalconductorsextending through saidenvelope, one in contact with each of said pools, members above eachpool, each. adapted to restrict the exposed area: of its respectivepool, each of said restrict.- mg members comprising a part in contactwith its respective pool and a part overlying and masking a portion ofthe upper surface of its pool, each: restricting member being providedwith a. semi-conductive; surface, means; for electricallyconnecting thesemi-conductive surface of each restricting member to that oi the other,means forelectrically connecting saidconductors to a source ofalternating current, a current limiting ballast, means in saidconnectingmeans, and a plurality oi means for electrically joining; saidconductors and for joining the connections: from said: restrictingmembers.

12. In combination, an envelope of, insulating; material substantiallyfree fromair and shaped to, define, a pair of pool retaining: parts; apool of metal, which'remains liquidat normal operating; temperature, ineach of said pool retaining parts, said envelope defining a passagefrom. one.

pool to the other, electrical conductors extendingthrough said envelope,one in 'contact. with each of said: pools, members. above eachpool,each, adapted: to restrict the. exposed area of. its. respective; pool.each of said restricting: members:

comprising a. part incontact with; its; respective pool and apartoverlying. and masking a. pars. tion. ofthe upper surface: of. its:pool, each. restricting: member being; provided with a semi.-conduetive; surface, means for; electrically corrnecting: the;semi-conductive surfaces of each.-

trically joining said conductors and for joiningtheconnections-from saidrestricting members.

and a, rectifier positioned} in each of. said last.- rnentioned.connecting means, said. rectifiers be;- ing positioned outside said:envelope,

13. In; combination, an envelope of: insulating translucent. materialsubstantially; free: from; air

and shaped" to define a pair of pool; retaining; parts, a: pool ofmetal, which, is: liquid at; operatiing temperature. int eachfsaidretaminez'n rts said envelope defining a passage from one pool totheother, conductors extending through said envelope, one in contactwith each of said pools, means for electrically connecting saidconductors. to a source of alternating current, a current limitingballast in said connecting means, resistance elements within saidenvelope, one above each ofsaid'pools, said resistance members incontact with said pools, and means for electricallyconneoting to eachother parts of said two resistance members which are above said pools.

14-. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, said parts being shaped to restrict the exposed surfacearea of a pool of metal, which is liquid at, operating temperature, ineach of said retaining parts, said envelope defining a passage from one.pool to the other, conductors extending' through said envelope, one incontact with each.- of said pools, means for electrically connectingsaid conductors to a source of alternating current, a current limitingballast in said connecting means, resistance elements within said.envelope, one. above each of said pools, said resistance members incontact with said pools, and means for electrically connecting to eachther parts of said two resistance members which are above. said pools.

15. In combination, an envelope of insulating translucent materialsubstantially free from air and containing a pressure of not less thansev eral hundred microns of inert gas, said envelope shaped to define apair of pool retaining parts, a pool of metal, which is liquid at theoperating temperature, in each of said retaining parts, said envelopedefining a passage from one pool to the other, conductors extendingthrough said envzelope, one in contact with each of said pools, meansfor electrically connecting said conductors-to asource of alternatingcurrent, a current limiting ballast. in said. connecting means,resistanceelements with surfaces of resistance material freely exposedto space within said envelope, one of said resistance elements incontact with each; of said pools, means for electrically connesting toeach other parts or" two said resistance members which. are above. saidpools.

156. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at the operatingtemperature,.in each of said retaining partssai'd' envelope defining apassage from one pool to the other, conductors extending through saidenvelope, one in contact with each of said.

pools, means for electrically connecting said conductors tola source of.alternating current, a currentlimiting ballast insaid conducting means,resistance elements with surfaces of resistance material freely exposedto space within said envelope, one of said resistance elements incontactwith each" of said pools, electrical terminals not indirectcontact with the pools on each of said resistance members, electricalconnection from each terminal passing through a contact rectifier tothat metal pool with which the resistance element is in. contact, andmeans for electrically connecting terminals of the two resistancestoeach other.

L7. Incombination, an envelope of insulating translucent-materialsubstantially free from air and, shaped to: define a. pair of. poolretaining parts, said parts being shaped to restrict the exposed surfacearea of a pool of metal, which is liquid at operating temperature, ineach of said retaining parts, said envelope defining a passage from onepool to the other, conductors extending through said envelope, one incontact with each of said pools, means for electrically connecting saidconductors to a source of alternating current, a current limitingballast in said conducting means, resistance elements with surfaces ofresistance material freely exposed to space within said envelope, one ofsaid resistance elements in contact with each of said pools, electricalterminals not in direct contact with the pools on each of saidresistance members, electrical connection from each terminal passingthrough a contact rectifier to that metal pool with which the resistanceelement is in contact, and means for electrically connecting terminalsof the two resistances to each other.

18. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at the operatingtemperature, in each of said retaining parts, said envelope defining apassage from one pool to the other, conductors sealed through saidenvelope, one in contact with each of said pools, means for electricallyconnecting said conductors to a source of alternating current, a currentlirni iting ballast in said conducting means, resistance elements withsurfaces of resistance material freely exposed to space within saidenvelope, one of said resistance elements in contact with each of saidpools, electrical terminals not in direct contact with the pools one oneach of the resistance members, electrical conductors from each of saidterminals sealed through said envelope, said conductors electricallyconnected to each other outside of said envelope.

19. In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a pool of metal, which is liquid at the operatingtemperature, in each of said retaining parts, said envelope defining 'apassage from one pool to the other, conductors sealed through saidenvelope, one in contact with each of said pools, means for electricallyconnecting said conductors to a source of alternating current, a currentlimiting ballast in said conducting means, resistance elements withinsaid envelope, one in contact with each of said pools, electricalterminals not in direct contact with the pools, one on each of theresistance elements, electrical conductors from each of said terminalssealed through said envelope, said conductors electrically connected toeach other outside of said envelope, and said conductors connected tothe conductors in contact with the pools by means of contact rectifierslocated outside of said envelope.

20. In combination, an envelope of insulating material substantiallyfree from air and shaped to define a pair of pool retaining parts, apool of metal, which is liquid at operating temperature, in each of saidretaining parts, said envelope defining a passage from one pool to theother, conductors extending through said envelope, one in contact witheach of said pools, means for electrically connecting said conductors toa source of alternating current, a current limiting ballast in saidconducting means, semi-conducting funnel-shaped members above each pool,each adapted to restrict the area of its pool exposed to the electricaldischarge, each of said funnels comprising a part in contact with itsrespective pooland overlying and masking a portion of the upper surfaceor" its pool, an electrical terminal at the large end of eachsemi-conducting member, means for electrically connecting the saidterminals to each other inside of the envelope, and means forelectrically connecting each terminal through a contact rectifier to thepool, the physical position of said contact rectifier being in the spacebounded by the pool, the funnel, and that portion of the envelopesurrounding the funnel.

21; In combination, an envelope of insulating translucent materialsubstantially free from air and shaped to define a pair of poolretaining parts, a, pool of metal, which is liquid at the operatingtemperature in each of said parts, said envelope defining a passage fromone pool to the other, conductors extending through said envelope, onein contact with each of said pools, means for electrically connectingsaid conductors to a source of alternating current through some currentlimiting device, resistance elements within said envelope and in contactwith each pool, said elements electrically connected to each other, thecurrent through said resistance elements initiating a cathode spot whena pool becomes negative, the potential distribution attending the flowof current in said resistance elements causing the transfer of theelectron current originating at the spot through the gas in saidenvelope to the electrode which is temporarily positive.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 803,836 Lunt Nov. 7, 1905 1,178,542 Skaupy Apr. 11, 19161,889,079 Sperti Nov. 29, 1932 2,006,466 Ludwig July 2, 1935 2,020,736Pirani et al Nov. 12, 1935 2,157,923 Slepian May 9, 1939 2,160,583 CageMay 30, 1939 2,215,804 West Sept. 24, 1940 2,218,386 Smith Oct. 15, 19402,495,831 Warmoltz Jan. 31, 1950 FOREIGN PATENTS Number Country Date461,380 Germany June 22, 1928 59,321 Holland Apr. 15, 1947

